Amp issues :(

[dougee]

Hey, First post on this forum!!! Hopefully I can become an active member

Finally got around to installing these items today :
PG ZX450
Hat L1v2's
Dyn MW152's

Running active with crossovers set on the amp, bypass for the mids and hp for the tweet.

Noticed in some prelim listening that one side sounded louder, upon further investigation realised it was the right mid (rear right channel on the amp)
The input to the amp is definitely the same on both the left and right channel however the amp is outputting double the ac voltage to the left rear channel vs the right rear channel.

I have tried swapping the woofers from left to right, the same output issue persisted in that side.

Hence im thinking it must be the amp. Where should I start looking inside? any ideas? Fets, caps?

Add :
Just pulled it apart



board is very clean, it appears to have been dissasembled before as the ribbon cable has been de-soldered at some point.


this is the output speaker connections. Any possibility this could be the issue?

[Mr. Wild]

I would start by checking the ribbon cable solders since they have been touched. The ribbon cable carries the signal from the crossover card to the amp section I think.

[holmis]

Tryed switching the signal (RCA`s) ?

[dougee]

Will do! they look pretty much just as bad :/ is it worth resoldering what looks bad?

and yeah its definitely an output issue, i switched the rca's (left to right) and the problem still persisted with that channel

I will do a bench test later today just to double check though.

Thanks Guys

[valeks1]

Check fan it's installed backward. If you keep this way right channels will overheat.

[stipud]

Also with a ZX the pots are known to oxidize. Turn the gain, bassboost, crossover, etc. knobs up and down a bunch of times to see if there's any improvement.

[dougee]

Are you serious? I havnt touched the fan.. starting to hate whoever worked on it :/

will be testing it a soon, will let you know what I come up with.

[dougee]

Well I cleaned all the solder joints, they appear to be fine.. Rotated all the pots several times.. and flipped the fan over, it was indeed blowing in the wrong direction.

And bench tested, it appears to be fine. left and right channels are balanced I will be installing it again very soon. I really hope it was just THAT easy, fingers crossed.

Just a question, would you guys replace the caps on the amp? there is a slight bit of bulging on the top of the left 4, not much though.

[dougee]

Reinstalled, and by ear sounds 100%. All I can say is Thanks!
Sounds brilliant now

[stipud]

Definitely recommend going over the powersupply input caps before they start to leak and short out. The rail caps are normally more reliable, but not that hard to swap either. You can fit in higher capacitance ones as well, which gives a sliver more headroom on music. In the meantime, enjoy! The 450 is easily the most versatile amp, and they usually put out 100-115x4w before clipping

[ttocs]

yes on caps.